The present invention relates to a system including a portable identification medium, for example in the form of a card, and a control unit with which information which is encoded on the identification medium can be read, the control unit allowing a user to access the system once the identity of the identification medium has been established.
Such systems in which a user identifies himself via an identification medium are known in many forms. In this connection, the medium serves as a key for access to the system. In the process, the medium is presented to the control unit and, as soon as the control unit establishes that the medium is authorized, i.e., a matching key, it enables access to the system. In the known systems heretofore, a numeric code, for example, a customer number is stored on a magnetic strip or a chip on the medium, i.e., a card, as individualizing information. The code is then read out via a corresponding reader device integrated in the control unit and is checked by a computer.
In these systems, it is a disadvantage that not only the medium must be equipped with a magnetic strip or a chip, which requires a comparatively large expenditure of effort and money but, above all, that the control unit must be provided with a device for reading out the information, involving a corresponding degree of expenditure. Thus, the control unit must have, in particular, an intake for the medium. This intake, for example, a slot having an appropriate mechanism, requires considerable outlay and is susceptible to vandalism.
Known are, moreover, such systems in which the code is transmitted acoustically with the assistance of an electronic tone generator located on the medium. In these systems, the medium requires a large expenditure of effort and money because of the generator. Besides, the transmission is very unreliable and frequently gives rise to system errors. Moreover, devices in the form of cards are known which have a toothed profile on one edge, the information being encoded in the arrangement of the teeth. The acoustic signal is generated by sweeping an object over the profile, a noise developing in the process. In this context, it is a disadvantage that, in addition to the medium, a further object must exist which is used to generate the signal. Due to the additionally required object, the system is complex and unpractical. Besides, the signal is reproducible only with difficulty since it depends on the speed and completeness of the sweeping movement.
Also known are systems which bring about an identification via spoken speech. These systems are complex and not very reliable since they are dependent on a plurality of incalculable parameters.
Therefore, an object of the present invention is to provide an access-controlled system which is rugged, easy to handle and inexpensive to manufacture while being highly reliably and reproducible. It is also an object of the present invention to provide an identification medium which supports the system according to the present invention and at the same time is reliable, rugged and inexpensive.
The present invention provides an access-controlled system. The access-controlled system includes a portable identification device including an element configured for generating a reproducible acoustic signal in a mechanical manner, a frequency spectrum of the signal encoding an information. Also included is a control unit configured for reading the encoded information and for allowing a user to access the access-controlled system upon an establishing of an identity of the identification device.
According to the present invention an acoustic signal-generating device is attached to the identification medium which, after a mechanically applied force has acted thereon, for example, subsequent to a pressing by the user, emits an acoustic signal by which the medium can be identified. To enable a reliable identification, it is required for the acoustic signal, whose frequency spectrum encodes information, to be reproducible. A generated signal must correspond to each further generated signal as exactly as possible.
It is conceivable for such a system to be used in many areas. Thus, it is possible for telephone cards or credit cards to the be provided with the device according to the present invention. In the case of a telephone card, the acoustic signal would be picked up via a microphone of the telephone system, for example, through the handset, and sent to a central computer via the telephone line. The central computer would then carry out the billing of the telephone call, the billing being allocated to the owner of the card via the acoustic signal. In the case of a credit card, it would be possible for the customer or account number of the card holder to be encoded in the signal. In this context, however, it is advantageous if the user authorizes himself/herself by entering a PIN code which is only known to him/her into the control unit.
It is a particular advantage of the present invention that systems of that kind are rugged and simple. Thus, the acoustic signal can be picked up by a simple microphone which is integrated in the control unit. Complicated electronics featuring a read head and, above all, the insertion aperture can be dispensed with. In this context, known systems, in particular speech recognition systems, are available for evaluating the acoustic information. The system makes it possible for the medium to be reliably identified.
In principle, strings, rods, tongues, membranes, plates or air columns can be used as signal-generating device. However, it is particularly simple and, therefore, advantageous, if the signal-generating device features a tongue and/or a curved surface which is attached onto the medium in such a manner that it/they can be acted upon by a user pressing with a finger against a resistance, and that it/they emit(s) the signal (xe2x80x9cclackxe2x80x9d) when the resistance is overcome. Devices of that kind are known as toys (frog clickers). After the clacking threshold is overcome, the device springs back to the initial position. In this context, the mostly different noise (xe2x80x9cclickxe2x80x9d) emitted while springing back can also be used for encoding information.
In this context, in an embodiment, the encoding of the information is effected by the individual shaping of the tongue or surface and/or by the design of their suspension, i.e., for example, by changing the resistance to be overcome. Extensive tests have shown that such a device can generate an individual signal from whose frequency spectrum the coded information can be reliably read, advantageously after a Fourier transformation. In the course of time, the characteristic does not or only slightly change, it being possible for such a change to be allowed for via the computational algorithms. It is also conceivable for the information to be encoded by individually shaping the resonator, the individualization having to be effected by more significant measures in this case.
It is a special advantage of the medium according to the present invention that no complex electronics and, in particular, no battery are included so that its disposal does not create any problems. At the same time, the xe2x80x9cfrog clicker functionxe2x80x9d is easy to be implemented, offering a large variability of the encoded information, and can easily be integrated in a rugged medium, in particular, in the form of a card. Such a card having an integrated xe2x80x9cfrog clicker functionxe2x80x9d is durable and stands out by its compact design. In addition, it is easy and inexpensive to manufacture and particularly suitable for use in telecommunications media that use the speech frequency band. It should be pointed out as an advantage that the signal-generating medium according to the present invention does not require any further aids as were needed in related art heretofore.
In an embodiment, the tongue or curved surface are integrally formed on the identification medium which is designed as a card. To produce a resistance, it is advantageous for the tongue to be provided with a longitudinal groove or with walls which project perpendicularly to the top surface of the card. A xe2x80x9cclackingxe2x80x9d effect can also be attained via a peripheral clamping on both sides. The integral formation provides a good coupling of the device to the resonator and, in this manner, a correspondingly good sound amplification.
It is particularly advantageous if the encoding can be carried out by the user himself/herself. To this end, the user can be given corresponding possible methods. Thus, the user receives, for example, a card whose tongue which does not have any changes yet and which therefore emits a basic noise. The individualization is then carried out by the user via punching or pressing depressions into the tongue, or by shaping the curved surface. In this context, the mechanical variation brings about an acoustic variation. The noise generated in this manner is subsequently stored in a data base together with the necessary information. Thus, the card is initialized.
In an embodiment, the medium is designed as a key tag, thus being handy at any time and relatively unlosable. Moreover, it can be advantageous to provide the medium, in particular the card, with a magnetic strip and/or with a chip or to provide known cards with a device according to the present invention for generating an acoustic signal. In this context, the acoustic signal can be used for a redundant individualization so that security is further increased.